<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>02变量与常量</title>
</head>
<body>
<script>
    //js是一种弱类型语言
    //1.使用var关键字声明变量
    var a = 10;
    var b = 3.14;
    var c = "hello";
    var d = true;
    console.log(a,b,c,d);
    console.log(typeof a,typeof b,typeof c,typeof d);
    a=6.6;
    console.log(a,typeof a);
    a=false;
    console.log(a,typeof a);
    var  a ='哈哈哈我又来了';
    console.log(a,typeof a);

    let x =1;
    console.log(x,typeof x);
    x=6.6;
    console.log(x,typeof x);


    const y=1;
    console.log(y,typeof y);


</script>

</body>
</html>